Such liquid mist separation devices are based on an inertia principle. The gas flow is accelerated through the nozzles and directed against the baffle plate. On the baffle plate, the liquid droplets which are carried along in the gas flow are driven out from the gas flow owing to the inertia, and strike onto the baffle plate, on which they remain caught. For an effective liquid mist separation, the speed of flow of the gas flow through the nozzle must be as high as possible. Therefore, the flow cross-section of the nozzles should not be too large. However, a small flow cross-section brings about a high backup and therefore a high loss of pressure. Here, a compromise of the cross-sectional area is expedient, in which the pressure losses are not too high, but the separation is sufficient for the system. This compromise can, however, always only be optimal for one volume flow.
Therefore, it is known to equip the liquid mist separation device with variable nozzles, which have a variable nozzle cross-section, so that at higher through-flow rates the overall nozzle cross-section can enlarge and thereby the loss of pressure which is caused is reduced.
From DE 10 2006 024 816 A1 for example a so-called impactor is known. The impactor has a spring-loaded poppet valve which, on opening, forms an annular gap and therefore forms a variable nozzle.
However, these liquid mist separation devices usually have the disadvantage that the gas flow is deflected before it flows through the at least one nozzle and thereby also loses kinetic energy, whereby a pressure loss is produced.
From WO 2011/089006 A1 a valve is known for controlling a gas flow, in particular in a crankcase ventilation device. Here, a liquid mist separation can be achieved with the valve. For this, several gas through-openings are provided in the valve plate, which function as nozzles. Opposite the valve plate, a separation element is arranged. However, no separation element is associated with the variable valve gap.
From EP 2 963 258 A1 a liquid mist separation device is known, which has a nozzle plate and a baffle plate which is displaceably arranged with respect to the nozzle plate. Projections are arranged on the baffle plate which, depending on the position of the baffle plate, engage into the nozzles of the nozzle plate and therefore influence the cross-section of the nozzles.